An assessment of the basis of mercury tolerance in Dunaliella tertiolecta

1976 ◽  
Vol 56 (1) ◽  
pp. 39-57 ◽  
Author(s):  
Anthony G. Davies
Keyword(s):  
Cell Membrane ◽  
Culture Medium ◽  
Isochrysis Galbana ◽  
Giant Cells ◽  
Dunaliella Tertiolecta ◽  
Sensitive Species ◽  
Compound Formation ◽  
Permeability Changes ◽  
Sulphydryl Groups ◽  
Mercury Tolerance

The specific growth rate of Dunaliella tertiolecta was unaffected by mercury II concentrations of at least 2.03 μg at/1. At 10 μg at/1, it was eventually reduced by 84% but growth continued, giving a final level of cell material only 13% below that in a mercuryfree control. At this concentration, however, growth was largely uncoupled from division and giant cells were produced, probably due to the effect of mercury upon the production of methionine which is known to be implicated in the process of cell division.The basis of the mercury tolerance was investigated in terms of (1) mercury detoxication in the culture medium by complex or compound formation between the metal and metabolites produced by the cells, (2) the concentration of sulphydryl groups both within the cells as possible sequestration sites and in the cell membrane where any molecular disruption and permeability changes produced by the metal first occur, (3) the absence of cellular potassium leakage and (4) the resistance of the cell membrane to the uptake of mercury II ions. Where possible, the results were compared with those from determinations of the same properties of the mercury-sensitive species Isochrysis galbana. The experiments indicated that the mercury tolerance of D. tertiolecta is partly related to the slower rate of mercury accumulation by this species, but is largely due to the detoxication of the mercury within the cell possibly by the precipitation of a highly insoluble mercury compound

scholarly journals DRY WEIGHT, CARBON, C/N RATIO, HYDROGEN, AND CHLOROPHYLL VARIATION DURING EXPONENTIAL GROWTH OF SELECTED MICROALGAE SPECIES USED IN AQUACULTURE

2015 ◽  
Vol 30 (1) ◽  
pp. 33
Author(s):  
A. Pérez -Morales ◽  
A. Martínez -López ◽  
J. M. Camalich -Carpizo
Keyword(s):  
Growth Rate ◽  
Exponential Growth ◽  
Food Source ◽  
Culture Medium ◽  
Isochrysis Galbana ◽  
Dry Weight ◽  
Dunaliella Tertiolecta ◽  
Physiological Indicators ◽  
Nutrients Uptake ◽  
Chaetoceros Calcitrans

Microalgae are commonly used as food source in aquaculture, mainly for shellfish and larvae of crustacean and fish. All hatcheries need an excellent inoculum to produce high-quality microalgae when cultured outdoor in extensive systems, and this depends largely on the health of the microalgae cultured under laboratory conditions as a primary step. Therefore, the aim of this work was to assess variations of dry weight, carbon, C/N ratio, hydrogen and chlorophylls as physiological indicators of nutrients uptake and growth rate during exponential growth of Isochrysis galbana, Chaetoceros calcitrans and Dunaliella tertiolecta, using f/2 as culture medium. Chaetoceros calcitrans and D. tertiolecta had higher carbon content (~30 pg cell-1). The C/N ratio varied widely, gradually decreasing on I. galbana. Chlorophyll a varied among the three microalgae tested, ranging from 0.25 pg cell-1. Growth rate was higher in I. galbana (K’ 0.83) followed by D. tertiolecta and C. calcitrans. Results showed that nutrient incorporation by cell change when cell density increases; this information provides new insights in the physiology of marine microalgae and confirms that nutrient uptake dynamics is different in each microalga species. Finally, this study indicates that using one culture medium is not equally efficient for all microalgae used in aquaculture since each species has specific nutritional requirements. Variación de peso seco, carbono, relación C/N, hidrógeno y clorofilas durante el crecimiento exponencial de especies selectas de microalgas utilizadas en acuacultura Las microalgas son comúnmente utilizadas como fuente de alimento en acuacultura, principalmente para cultivo de moluscos y para las fases larvarias de crustáceos y peces. Los criaderos de larvas necesitan un excelente inóculo para producir microalgas de alta calidad cuando se cultivan al exterior en sistemas extensivos; esto depende principalmente de la salud de las microalgas cultivadas bajo condiciones de laboratorio como primer paso. Por lo tanto, el objetivo de este trabajo fue evaluar variaciones de peso seco, carbono, relación C/N, hidrógeno y clorofilas como indicadores fisiológicos de la asimilación de nutrientes y tasa de crecimiento durante el crecimiento exponencial de Isochrysis galbana, Chaetoceros calcitrans y Dunaliella tertiolecta, usando f/2 como medio de cultivo. Chaetoceros calcitrans y D. tertiolecta presentaron el mayor contenido de carbono (~30 pg cél-1). La relación C/N varió ampliamente, decreciendo gradualmente en I. galbana. La clorofila a fue la que más varió entre las tres microalgas evaluadas, en el intervalo de 0.25 pg cél-1. La tasa de crecimiento fue mayor en I. galbana (K’ 0.83) seguido por D. tertiolecta y C. calcitrans. Los resultados mostraron que la incorporación de nutrientes por célula cambia cuando la densidad celular se incrementa; esta información provee nuevo conocimiento sobre la fisiología de microalgas marinas y confirma que la dinámica de incorporación de nutrientes es diferente en cada especie de microalga. Por último, este estudio indicó que el uso de un solo medio de cultivo no es igualmente eficiente para todas las microalgas usadas en acuacultura, debido a que necesitan requerimientos nutricionales específicos.

Depression of Carbohydrate in Marine Algae by Urea Herbicides

Weed Science ◽  
1971 ◽  
Vol 19 (5) ◽  
pp. 568-570 ◽  
Author(s):  
Gerald E. Walsh ◽  
Thomas E. Grow
Keyword(s):  
Marine Algae ◽  
Isochrysis Galbana ◽  
Carbohydrate Content ◽  
Dunaliella Tertiolecta ◽  
Unicellular Algae ◽  
Representative Species ◽  
Unialgal Culture

Representative species of six genera of marine unicellular algae (Chlorococcumsp.,Dicrateria inornataParke,Dunaliella tertiolectaButcher,Nannochlorissp.,Isochrysis galbanaParke, andMonochrysis lutheriDroop) were treated in unialgal culture with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), 1-butyl-3-(3,4-dichlorophenyl)-1-methylurea (neburon), 3-(p-chlorophenyl)-1,1-dimethylurea (monuron), and 1,1-dimethyl-3-phenylurea (fenuron). Tests were conducted at salinities of 5, 10, 20, and 30 parts per thousand (ppt). The herbicides depressed concentration of carbohydrate in all species.Dunaliella tertiolectawas most resistant; its carbohydrate content decreased 9.2% at 5 ppt salinity and 17.9% at 30 ppt.Chlorococcumwas most susceptible; its carbohydrate content decreased 49.1% at 5 ppt and 65.6% at 30 ppt salinity.

WATER PERMEABILITY CHANGES OF THE CELL MEMBRANE AS A FUNCTION OF TIME

2005 ◽  
pp. 1117-1124
Author(s):  
I. Sotome ◽  
J. De Baerdemaeker ◽  
S. Oshita ◽  
Y. Kawagoe
Keyword(s):  
Cell Membrane ◽  
Water Permeability ◽  
Permeability Changes

On the appearance of Bacillus subtilis intracellular serine protease in the cell membrane and culture medium

1978 ◽  
Vol 119 (3) ◽  
pp. 287-293 ◽  
Author(s):  
Alexander Ya. Strongin ◽  
Lara S. Izotova ◽  
Zakhar T. Abramov ◽  
Lidia M. Ermakova ◽  
Dmitrii I. Gorodetsky ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Cell Membrane ◽  
Serine Protease ◽  
Culture Medium

Circulatory Reaction of Tolerant and Nontolerant Dogs to Polyvinylpyrrolidone and of Rats to Dextran

1957 ◽  
Vol 189 (1) ◽  
pp. 209-213 ◽  
Author(s):  
L. H. Marshall ◽  
C. H. Hanna
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Intravenous Injection ◽  
Mean Arterial Blood Pressure ◽  
Capillary Permeability ◽  
Sensitive Species ◽  
Pressure Pattern ◽  
Arterial Blood ◽  
Permeability Changes

In dogs the decrease in mean arterial blood pressure and appearance of gross signs after rapid intravenous injection of 350 mg PVP/kg became less severe after pretreatment with the colloid. When the same dosage was injected 1 hour previously, the reaction was completely absent in 9 dogs out of 12, and the remainder were relatively refractory. Refractoriness in rats to a second injection of dextran (600 mg/kg) was demonstrated in the same manner. The blood pressure pattern, erythema and edema with extravasation of dye indicate that both colloids produce in the sensitive species an initial vasodepressor action followed by capillary permeability changes. No vasodepressor reaction occurred in relatively tolerant dogs given dialyzed PVP.

Water and electrolyte contents, cell pH and membrane potentials of cultured turtle thyroid cells

1985 ◽  
Vol 104 (1) ◽  
pp. 45-52 ◽  
Author(s):  
S. Y. Chow ◽  
Y. C. Yen-Chow ◽  
D. M. Woodbury
Keyword(s):  
Membrane Potential ◽  
Cell Membrane ◽  
Culture Medium ◽  
Resting Membrane Potential ◽  
Follicular Cells ◽  
Iodide Uptake ◽  
Thyroid Cells ◽  
Cell Ph ◽  
Cells Cultured ◽  
In Cells

ABSTRACT Water and electrolyte contents, cell pH, membrane potential and 125I− uptake were determined in cultured follicular cells of turtle thyroid. The Na+, K+ and Cl− concentrations in the cultured thyroid cells were 59·2, 119·0 and 50·9 mmol/l cell water respectively. Treatment with TSH (10 mu./ml for 24 h) increased the K+ and Cl− and decreased the Na+ concentrations in cells. The water and protein contents of these cells were 81·6 and 8·7 g/100 g cells respectively. The cell pH was 6·91. With glass microelectrodes, the resting membrane potential of thyroid cells cultured in Medium 199 averaged 33·9 ± 0·63 mV which is slightly higher than 29·8 ± 1·6 mV as calculated from the data on the uptakes of [14C]methyltriphenylphosphonium and 3H2O by the cells. The potential varied linearly with the log of external K + concentration (between 15 and 120 mmol/l) with a slope of about 24 mV per tenfold change in K+ concentration. Both TSH and cyclic AMP depolarized the cell membrane. Calculations based on the values for the electrolyte concentrations in cells and in culture medium indicated that Na+, K+ and Cl− were not distributed according to their electrochemical gradients across the cell membrane. Na+ was actively transported out of the cells and K+ and Cl− into the cells. Follicular cells of turtle thyroid cultured in the medium without addition of TSH formed a monolayer. Their iodide-concentrating ability was low and they did not respond to TSH with an increase in iodide uptake. In contrast, cells cultured in medium containing TSH tended to aggregate and organize to form follicles. They had higher ability to concentrate iodide and respond to TSH. J. Endocr. (1985) 104, 45–52

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